The present invention is directed generally to pulse counters, and more particularly to an electromechanical pulse counter providing a high degree of reliability in adverse operating environments.
It is frequently necessary to indicate the number of occurrences of an electrical event, such as the occurrence of a fault current or a lightning strike, in a power distribution system. For example, a count may be required of the number of fault currents occurring over a period of time at an exposed relatively inaccessible location in the system to assist in locating the source of the fault. In such instances the counter utilized to count the fault occurrences must reliably operate in extremes of heat and cold and environmental contaminants, and must be readily viewable from a distance and without access to the counter.
Previously, counters employed for this purpose utilized a solenoid-actuated mechanism to drive a series of counter wheels on which indicia exposed through a viewing window indicated the number of occurrences of the electrical event being counted. Not only was this type of mechanism subject to malfunction from adverse environmental conditions, which tended to interfere with operation of the actuating mechanism, but the relatively large currents required to reliably actuate the mechanism were sometimes not readily available from the associated monitoring circuitry. A further disadvantage of such types of counters was that they were difficult to read from a distance and relatively expensive to manufacture, particularly when environmental conditions had to be taken into account.
The present invention is directed to an improved electromechanical pulse counter, which by avoiding the use of counter wheels and an associated solenoid actuator mechanism, provides a less costly and more reliable construction for use in adverse operating environments.